Add [package.metadata.cargo-deny]

[Jake-Shadle]

Currently all configuration is done via deny.toml, however this makes it so that doing more localized opt in/out of particular lints etc is tedious since they need to be done globally. One idea prompted by #664 would be to add support for a package specific cargo-deny section that can make these kind of tweaks more easily, as well as just add new capabilities like those mentioned in #664, allowing dependencies to notify cargo-deny users without the user needing to update their workspace config.

Another candidate for this feature is possibly the ability to opt-out of [workspace.dependencies] lints for the crate, or 1 or more specific dependencies in the crate, as unfortunately the idea for opt-out I originally had, setting workspace = false doesn't work since cargo only allows workspace = true. That being said, I don't really have a use case that needed this functionality immediately, but I just suspect it will be complained about in weird situations that I'm not aware of.